The invention relates to contacts for an electrical connector and, more particularly, to a folded contact for receiving and connecting electrical component leads.
For certain applications, such as integrated circuit connectors, it is desirable to make electrical contact with each component lead at a plurality of different points to enable a more reliable connection with bent or misorientated leads.
Prior art approaches to solving this problem include contacts having a pair of opposed arcuate finger portions for gripping a lead therebetween. A two surface approach, while enhancing reliability somewhat, still does not circumvent the possibility of a bent lead extending away from between both surfaces. Further, arcuate contact portions do not provide as reliable a connection with a cylindrical lead as do sharp biting edges.
Prior art contacts which completely surround a component lead have generally been of the type which comprises two parts, a cylindrical screw-machined holder and a tined insert. The insert includes a plurality of resilient inwardly and downwardly extending tines arranged in a conical configuration. Such contacts possess a number of inherent disadvantages; for example, both the fact that each contact is of two parts and the fact that one is made by screw machining contribute to the expense of the part. Further, the outer portion of these prior art contacts are cylindrical with annular, snap-in retaining ribs and are devoid of longitudinally extending angular edges adapted for press-fitting into a circular aperture in a substrate.
In general it is desirable to manufacture contacts from as thin metal stock as possible in order to reduce costs. However, when a thin flat contact is press fitted it into a circular plated-through hole, it may be easily bent by transverse forces and, further gives a less reliable contact with the hole plating due to its thin knife-edge contact area. The folded contact of the present invention is made from relatively thin metal stock which, after folding, produces a contact having the same peripheral area as that of thicker stock but requiring substantially less material.
The folded contact of the present invention is especially adapted for use by press fitting into a cylindrical hole in a substrate. Prior art press fitted contacts have relied upon a rigid transversely extending shoulder and a solid press fitting neck section having longitudinally extending angular edges to slightly deform the walls of the hole and form a tight frictional fit therewith. The preferred embodiment of the folded contact of the present invention includes a shoulder-less four-sided press fitting central portion which is generally rectangular in cross-section and open down the center. The folded structure is sturdy enough for press fitting against the top of the contact and includes four longitudinally extending angular edges for engagement with the walls of the hole and a hollow cross-section that, when press fitted, resiliently deforms along with the walls of the hole to give a highly reliable frictional engagement. More particularly, the press fitted contact portion is deformed from a rectangular cross-section to a more oval or rounded shape which resiliently presses outwardly against the walls of the hole and holds the contact firmly in position.
The folded contact of the present invention overcomes many of the cost and reliability problems or prior art lead contacts while being simple to manufacture and press fit into holes in a substrate. Further, the folded contact of the present invention is readily adapted for use in the method and connector disclosed and claimed in co-pending U.S. patent application Ser. No. 406,931, filed by J. Preston Ammon Apr. 15, 1974, entitled "Low Profile Integrated Circuit Connector and Method" and assigned to the assignee of the present invention.